Eico HF 12 User manual
12
WATT I NTE GRAT ED
HIGH
FIDELITY
AMPLIFIER
MOD
E L
HF-12
I N S T R U C T I O N
MANUAL
HF
"-3
ELECTRONIC
INSTRUMENT
CO.
INC.
3300
NORTHERN BLVD
.,
L.
I.
CITY
1,
N. V.
MODEL
HF
12
12
WATT
INTEGRATED
HIGH
fIDELITY
AMPLIfIER
general
description _
GENERAL
The HF12 is a true high
fidelity
12-watt
integrated
ampl
i-
fier absolutely free of the "gimmi cks" sometimes used in
low-priced amplifiers. It provides complete "front end"
facilities and true high
fidelity
performance of such
ex-
cellence
that
we can recommend it unreservedly for
any
medium-power
high
fidelity
application.
Two HF 12's
may be used for stereo
tape
reproduction,
each
amplifier
connecting
directly
to a
tape
headwith no
other
electronic
equipment
required.
FEATURES
1. Two low level inputs far magnetic phono (RIAA) and
tape head (NARTB).
Low
noise dual triode preamplifier
with
accurate,
lowdistortion
equal
izatlon
for
either
Input.
SPECIFICATIONS
Output Power: 12 watts
continuous,
25 watts
peak.
2.
Two high level inputs for
tv,
tuner,
and crystal or
ceramic ca rtridge.
3.
Unused inputs are shorted
at
every
position of the
in-
put
selector
switch for
zero
cross-talk.
4.
DC superimposed on all tube filaments to eliminate
cathode-heater
leakage as a source of hum.
5. Low-noise dual triode used
exclusively
for
separate
bass and
treble
tone controls. Extremely low
distortion,
variable
crossover,
feedback-type
circuit.
6. Highly
stable
WilIiamson-type
powerampllfier
c
ircuit
.
7.
Newly-designed
"flat"
construction,
utilizing
horizon-
tal chassis to permit
properlayout
and
component
separa-
tion necessary for long component
life.
Extremely flex
ible
design permits
easy
console
installation
with
com
pie
t e
sh
ielding
and
adaptability
to
any
panel thickness.
*
1M
Distortion (60 &6000 cps
at
4:
1):
1.3%
at
12 W;
0.55%
at
6W;
0
.3%
at
4W.
*Frequency Response: 1W :
±0.5db
12 cps -
75kc;
12W:
±0.5db
25 cps _
20kc.
*Harmonic Distortion:
20cps:
2%
at
4
.2W;
1/2%
at
2.5W;
30cps
: 2%
at
11W;
1/2%
at
6.3W;
40cps
: 1%
at
12W;
1/
2%
at
9.3W;
2000 cps :
1/2%
at
12W;
10kc
: 1%
at
lOW;
1/2%
at
6W.
*Transi
ent
Response:
excellent
square
wave
reproduction (4 usec risetime);
negligible
ringing,
rapid
settling
on 10kc .
square
wave.
*Transient Distortion (60 cps tone burst>: less than 1%
at
full power.
1COPYRIGHT(C) 1960
ElECnONIC
INsn UMENT
COMPANY
,Ine.
Inverse Feedback: 20 db
Stability Margin:
12db
Damping Factor: above 8, 20 cps - 15
kc.
Speaker Connections: 4,
8,
and 16 ohms.
Sensitivity (input for 12W): mag. phono - 5mv;
tape
head - 2mv; tuner, auxiliary -
0.5
v.
Hum
&Noise Level (below 12W): mag. phono - **60db; tape head - **50db; tuner, auxiliary -
75db
.
Tone Control Range: at
10kc,
:f:13db; at
50cps,
±16db
.
Tubes:
3-
ECC83/12AX7, 2- El84, 1- EZ81.
Size:
35/8"
high, 12"
wide,
81/4
"
deep.
Weight: 131bs.
* Meosured from high level Inputs with tone controls set at
"flat"
positions.
** IncIudes
effect
of compensation.
2
mechanical installation _
a)
HEAT
DISSIPATION (VENTILATION): In common with
other
electronic
equipment,
the
HF-12 produces
consider-
ableheatin
normal
operation.
Unless continuous and
ade-
quate
air
flow is
obtained
around
the
heat
producing
ele-
ments, these
elements
will
over-heat
and
their
useful
life
will be
greatly
curtailed.
It Is useful to understand
the
process of
convection
where-
by
heat
is removed In judging
the
suitabilltyofa
location.
Air
heated
by
the
heat-producing
elements expands
and
rises; cool
air
is drawn from
beneath
to
take
the
place
of
the
heated
air.
In this
manner,
astream of
air
Is
set
in
motion which
continually
removes
heat
from
the
ampli-
fier. (In
particular,
we
are
mainly
concerned
with
the
mcler
heat-producing
elements;
the
two EL84
output
tubes
and the EZ81
rectifier
tube.)
If
there
Is
any
impediment
to or constriction
of
the
air
flow,
the essential process
of
heat
removal wi II be
adversely
affected.
Adequate
venti
lotion
will
be provided if the
amplifier
is
installed in
an
open-bock
console
provided
that
the
top
of the
amplifier
is
spaced
at
least
two Inches below
any
shelf mounted
above
It . If
the
cabinet
is
enclosed
at
the
rear,
provide several
large
holes or slots as low down
and
as high up in
the
cabinet
bock as
possible.
As an
alter-
nate,
holes may be provided In
the
sides,
bottom,
or top
of the
cabinet.
The
important
thing to remember Is
that
effective
ventilation
requires provision for cool
air
to
en-
ter
at
the
bottom and hot
air
to
leave
at
the
top .
If the
amplifier
Is not
installed
in a
console,
it
may be
situated on an
open
surface
or on a
shelf
of a
bookcase.
Four rubber
feet
arealso
provided so
that
the
ampliflerwil
I
not mar
the
surface
of
furniture
on
which
It
is
placed.
b) EASYACCESS TO
CONTROLS:
Mount
the
amplifier
ata
height
which
will
permit
easy
manipulation
of
the
con-
trols. Tuner
controls
should be
located
nearby
.
c) ACCESSABllITY TO
PARTS:
Tubes
are
the
most
fre-
quently
replaced
Items In
electronic
equipment.
If the
amplifier is
Installed
ina
console,
sufficient
spoce
should
bealloted
to
reach
and remove
any
tube
in
the
amplifier.
Furthermore,
input
and
output
terminals of
the
amplifier
should be
accessible
to
permit
easy
interchanging
of sys-
tem components for comparison, and
connection
or
dis-
connection of a portable
tape
recorder
which
is stored
a-
way when
not
In
use.
If
antennas
are
strung around the
back of the
console
In
which
the
amplifier
is
installed,
arrange them so
they
will
not
interfere
with
access
to
the
amplifier.
d) ACOUSTICAL ISOLATION: If
amplifier
and
speaker
are Installed In
the
same
cabinet
(not recommended),
pro-
vide
sufficlent
seporatlon
to
minimize
mechanical
speaker
vibration
reaching
the
ampllfi
er.
The minimum
seporatlon
Is
about
one
foot.
3
CONSOLE
MOUNTING
a)
Operations
on
console
front
panel
preliminary
to
am-
plifier
mounting: (1) Tape the
panel
template
provided
to
the
face
of
the
console
so
that
the top of the mounting
surface
line
on the
template
is level
with
the
top of the
amplifier
mounting
shelf.
(2) Use an awl or a nail to
pierce
the
centers
of
the
four
5/8"
diameter
holes for the
controls,
the
3/8"
hole
for
the
viewing of
the
pilot
lamp,
and
the
two smaII hoIes for mounting
the
contro
I pia
te,
to
transfer
their
locations
to
the
console
panel
beneath.
(3)
Remove
the
panel
template.
(4) DriII
the
holes for
the
ponel
controls
and
the
pilot
vi ewing hoIe
(the
two smaII
holes
which
have
been
marked
are
for wood screws).
b) Amplifier mounting in
console:
(1) Pull off
the
con-
trol knobs. (2) Remove the
control
plate,
which
is
at-
tached
to the
bezel
by two
screws.
(These may be
dis-
carded
since
they
are
unsuitable
for
attaching
the
control
plate
to the
console
panel
and
two
'4X3/8
wood screws
have
been
supplied for this
purpose.)
(3) Fasten
the
con-
trol
plate
to
the
console
panel
with
the
2
'4
X
3/8
wood
screws. (4) If the rubber
feet
have
been
inserted
in the
bottom
plate,
remove
them.
(They may be
pried
out
with
a
thin
screwdriver.
) (5) Remove
the
four screws
that
fasten
the
bezel
to
the
side
pieces
and
remove
the
bezel,
which
is not used in
console
mounting.
(6)
Place
the
unit
on
the
mounting
shelf
and
slide
it
as for forward as
possible,
so
that
the
controls
penetrate
the
panel
holes as for as
pos-
sible.
(7)
Place
a knob on
each
control,
pressing
each
knob toward
the
chassis firmly so
that
each
control
shaft
enters
fully
into its knob. (8) Draw
the
chassis bock
evenly
and
carefully
unti I the
back
rims of
all
the
knobs
are
equally
spaced
from the control
plate
about
1/8".
(9) With a
sharp
pencil,
draw the outline of the
side
and
rear
bottom
edges on the chassis
shelf.
As
the
bottom
plate
falls short
of
the
full
width
by 3
/16"
on
each
side,
draw new
side
edge
lines
3/16"
inside the
original
side
edge
lines.
(10)
Now remove
the
knobs
and
take
the chassis
off
the
shelf.
(11) Remove
the6
screws
which
fasten
the
bottom
plate
to
the
chassis. (12)
Place
the bottom
plate
exactly
in the
outline
drawn on
the
shelf
and
mark the
position
of the
center
hole
on
the
left
side
and
the
center
hole
on
the
right
side.
(13) Remove the bottom
plate
and
drill
each
of the marked holes on the
shelf
to a
diameter
of
1/4".
(14) Refasten the bottom
plate
to
the
chassis,
with
the
four
of
the
six 18 X
3/8
screws previously
removed,
using
the
two holes
at
the
rear
and
the
two holes
at
the
front of
the chassis. (15)
Replace
the chassis on the
shelf,
position-
ing it
exactly
in the outl
ine
previously
drawn,
and
restore
the
knobs. This time make sure
that
the
indicator
dot on
each
knob
agrees
with
the
control
position.
(16) From the
bottom
side
of
the
shelf,
insert
a18
XI"
screw,
with
01/2"
flat
washer
against
the
head,
through both
the
left
and
right
side
center
holes.
These screws
engage
the
stamped
nut
over
each
hole
on
the
chassis
flange
and
when
tightened
secure
the
chassis to
the
shelf
.
electrical Installation _
GENERAL
a)
SPEAKER
CONNECTIONS:
To
connect
your speaker
to the amplifier properly, you must know Its
rated
Imped-
ance
. This may be read off tne speaker
nameplate.
Con-
nect
one
speaker lead to
the"
G"termlnal
on the rear apron
and
tne
other
speaker lead to tne nearby terminal
corre-
sponding to the rated speaker Impedance (4,
8,
or 160hms).
Plastic-covered
lamp cord may be used for distonces up to
50 ft. wltn
little
power loss. For shorter
distances,
TV
ontenno lead
can
be
used,
particularly
If
It
Is desired to
run the speaker lead under a rug.
If
It
Is desired to use two similar or Identical
full-range
speakers of the same rated Impedance (either 8 or 16 ohms
only) for
better
sound distribution,
connect
one
speaker
lead of
each
pair to
"G"
and the two remaining leads to
the terminal with a number equal to half of
one
of
the
speaker's
rated
impedance. (It may be necessary to "phase"
the two speakers by reversing both of the leads from
one
of tne
speakers.)
This may not be done if
each
of
the
speakers Is designed for reproduction of a different
part
of the audio spectrum (woofer-tweeter combinations) In
which case across-ever network Is required which
con-
nects to
the
amplifier with only
one
pair
of leads.
b)
MAG.
PHONO
INPUT: This Input is intended for use
with phonographs having magnetic cartridges. The
shield-
ed
lead
from your phonograph should be provided wltn a
shielded
plug.
The loading reslstonce presented to the
cartridge
at
the Input Is
47,000
ohms, which Is the most
generally
suitable
loading resistance for magnetic
cart·
ridges.
c)
TAPE
HEAD INPUT: This Input Is Intended
fer
receiv-
Ing tne
output
signal
directly
from tne playback head of a
tape
deck.
NARTB
tape head
equalization
for 7
1/2
and
15
I.p.s.
tape
speeds Is applied to signals fed In
at
this
Input. The loading resistance presented to the
tape
head
Is 100
,000
ohms.
d) HIGH lEVEL INPUTS: Two high level Input Jacks
des-
Ignatedas
Tuner and Auxiliary
are
provided for connection
of tuners, tv
receivers,
equalized
and pre-ampllfled
tape
recorder
playback,
and ordinaryor
RIAA
equalizing
crystal
or
ceramic
phono cartridges without
adaptor.
Ashielded
cable
with ashielded
"phone-type"
plug should be used
to
connect
each
of these sources to the corresponding am-
plifier
input Jack. Unless the source has a low-Impedance
output such as a
cathode
follower{wlth which up to 50
ft.
of
cable
can be used), use tneshortestpasslble connectton
4
and low
capacity
snlelded
cable
(cable having as low
01
25mmfd
capacitance
per foot Is
availab
le) .
If ftle tuner employed has a valume control to adlust ftle
output,
set
this control to
give
about tne same sound level
for
any
given setting of the amplifier
VOlUM
Econtrol
01
obtained
from an
average
orchestra l recording
played
on
your phonograph. If you do
this,
there will not be
any
extreme
change
in sound level when switching from
phono-
graph to tuner or vice
versa.
e)
TAPE
OUTPUT: A shielded
cable
(up to 30 ft. may be
used) with a shie lded
"phone-type
" plug should be used
to
connect
from the
TAPE
OUTPUTlack to the Input of
the
~pe
recorder. Any input chosen by the
SELECTOR
Is fed
out
to the
tape
recorder through this
jack.
Phono inputs
fed In
at
MAG.
PHONO
are
of course
equalized
accord-
Ing to tne
RIAA
characteristic
and all the inputs are
af-
fected
by the level
and
tone controls.
f)
POWER
CONNECTIONS:
The 117VAC,
250W
re-
ceptacle
is
"live"
or
"dead"
depending on whether the
amplifier power switch is turned on or off .
By
plugging
Into It the line cordsof associated equipment (tuner,
tape
recorder,
etc.)
it is possible to turn these components on
or off with the amplifier. Use a
cube
tap if It Is desired
to
connect
more than one
device.
Record changers and
tumtables should be plugged into a wall
outlet
as a
pro-
tection to the mechanisms of these units.
HUM
ADJUSTMENT
a) After checking the amplifier for proper
operation,
re-
move all input cables to
the
amplifierand
makethe
follow-
Ing control settings which hold throughout the process of
hum adjustment:
SELECTOR
at
PHONO,
LEVEL
to 10,
TREBLE
centrci
at
-5,
BASS
control at O.
Next,
procede
01 follows: With your ear held close to the
speaker,
insert
the amplifier power plug into the wall
outlet
and listen to
tne hum
level.
Now pull out the plug and reinsert it with
tne prongs reversed and Iisten again . Choose the prong
position which gives the least hum. Now
connect
the
tuner
input
connector
to the amplifier input
jack,
andwlth
tuner
set between stations and the tuner volume control
set
at
minimum, do the same with the power plug of the
tuner,
using tne 117VAC
convenience
outlet
on the
amplifier
if
desired.Finally
connect
the phono input connector to
the
amplifler
MAG.
PHONO
or AUX. Input (as required)
and
find the lowest hum position for the power plug of
the
phonograph In a wall
outlet.
Do this with the phonograph
off and the pickup arm
at
rest position.
operation
_
PRELIMINARY:
Be
sure
all
tubes
arefirmly
seated
intheir
sockets and
that
the
VI
tube
shield is making good
contact
with its
base.
As
initial
adjustments,
set
these
controls
as follows: VOLUME
at
zero,
BASS
at
zero.
Turn
the
am-
plifier
on by turning the
TREBLE
control
clockwise
from
OFF and
set
It
at
zero
Initially.
Note
that
the
VOLUME,
BASS, and
TREBLE
controls
all
affect
the
TAPE OUTPUT.
LISTENING TO
PHONOGRAPH:
Set the SELECTOR to
PHONO
if you
have
a
magnetic
cartridge
or
AUXiliary
If
you
have
a
ceramic
-or crystal
cartridge.
The RIAA
equa-
lization
providedfor
magnetic
phono
cartridges
Is now
the
standard In
the
recording Industry and is also a
very
good
compromisefor the most importantof the
older
characteris-
tics. The
better
ceramic
cartridges
are
also
self-equalizing
according
to
the
RIAA
chorocter
lstlc
. Use
the
separate
bass
and
treble
tone
controls
to
compensate
for
inexact
matching
of
the
actual
recording
cha
racteristic
as
well
as
the
over-all
characteristics
of your
audio
system (Including
room
acoustics).
LISTENING TO
TAPE
DECK
(direct
connection
to
tape
head): Set
the
SELECTOR
to TAPE HEAD.
NARTB
tape
equalization
for the 7
1/2
and 15
I.
p. s. speeds is provided
by the
preamplifier-equalizer
at
this position. This
equali-
zation Is the industry standard for
pre-recorded
sterea
and
monaural
tapes.
The bass and
treble
tone
controls
can
be
used to
compensate
for
Inexact
matching
of
the
actual
re-
cording
characteristic.
LISTENING TO TUNER, TV,
TAPE
RECORDER
HAVING
BUILT-IN PLAYBACK
PREAMPLIFIER
- EQUALIZER: Set
the
SELECTOR
to TUN or AUX
depending
on
the
Input
desired.
The corresponding high level
input
will
feed
through
the
ampl
ifler.
Adjustment of the level control on
each
source
is discussed in
the"
ELECTRICAL
INSTALLA-
TION"
section
under"
High Level
Inputs".
MAKING
RECORDINGS: Tape recordings may be made
by
connecting
the
recorder
to the TApE OUTPUT
jack
. See
"Tape
Output"
under
"ELECTRICAL INSTALLATION"
Please
note
that
recordings
cannot
be made on
tape
decks
intended
only
for
sterea
or monaural
tape
playback
. Re-
cordings
can
only
be made on
tape
machines
having
record-
ing
facilities
including
the necessary el
ectronic
equipment,
whlchmaybe
either
built-in
or
supplied
seporately
by
the
tape
deck
manufacturer.
BASS
CONTROL:
The plus sign on the
right
side
of the
dial
indicates
that
clockwise
rotation
from
the
mid-point
(0) Increases (boosts) bass response;
the
minus sign on the
left
side
indicate
that
counter-clockwise
rotation
from the
mid-point
decreases
(cuts) bass response.There is no
in-
teraction
with
the
TREBLE
control.
Start
all
adjustments
with this
control
set
at
the
mid-point
(0), wh
ich
Is
called
the
"flat"
position s
ince
bass repsonse is ne
ither
cut
nor
boosted
at
this
setting
.
TREBLE
CONTROL:
The plus sign on
the
right
s
ide
of
the
dial
indicates
that
clockwise
rotation
from
the
m
id-po
int
(0)
increases
(boosts)
treble
response;
the
minus sign on
the
left
side
indicates
that
counter-clockwise
rotation
from
the
mid-point
decreases
(cuts)
treble
response.There is no
interaction
with
the
BASS
control.
Start
all
adjustments
with
this
control
set
at
the
mid-point
(0),
which
is
called
the
"flat"
position
since
treble
response is
neither
cut
nor
boosted
at
this
position.
maintenance
_
TROUBLE
SHOOTING &OPERATING NOTES
Your
amplifier
should
require
little
service
except
for
nor-
mal
tube
replacement.
We recommend no substitutions for
the
tube
types used in this
amplifier
except
as
stated.
All
the
tube
types used
are
distributed
nationally
,
but
replace-
ments
can
be
obtained
directly
from EICO If
desired.
To
facilitate
servicing,
remedial and
trouble-shooting
pro-
cedures
have
been
provided in
the
TROUBLE-SHOOTING
CHART
tho
tfollows. A VOLTAGE
AND
RESISTANCE
CHARTis a lso provided as an
aid
In
locat
ing
defective
components. DC
operating
voltages
are
given
both
at
no
signal and signal
developing
50
watts
output,
as wei I as
the corresponding I kc signal
voltages.
cal'"C
l n u
cr":]"-ClCIf"!II~II
C
.
5
TROUBLE-SHOOTING
PROCEDURES
Connect
aphonograph
and
speaker
to
the
amplifier as
de-
scribed in
"Electrical
Connections"
and set
controls
for
phono
listening.
Playa
known high
quality
LP
recording
on the phonograph . If
there
is no
output
to
the
speaker
or if the
output
Is low or
audibly
distorted,
procede
to the
checks
for those symptoms. If
there
is
excessive
hum in
the
output,
disconnect
the
phono
input
cable
from
the
amplifier
and short the phono
input
jack
to chassis. If
the
hum
disappears,
the
trouble
is
not
in
the
amplifier
but in
the
phonograph or in
the
connection
to
the
ampl
ifier
.
The
cause
of phonograph hum may be a metal
pick-up
arm
not
grounded to
the
cable
shield
(try a good
single
ground
connection
to the
cable
shield
from
turntable
frame,
pick-
up
arm,
and
cartridge
case),
dired
hum
pick-up
by the
magnetic
cartridge
from
the
record
player
motor (try using
arubber mat on the
turntable
to
Increase
the
separation
of
the
pick-up
from
the
motor), or
pick-up
from a power
trans-
former
or
other
magnetic
field
in
the
vicinity
(try moving
phonograph
away
from suspected
source).
Check
also
that
the
phono
input
cable
shielding
Is grounded to
the
ampli-
fier chassis
at
one
point
only
through
the
skirt
of
the
Input
connector
where
it plugs Into
the
amplifier.
Finally,
try
agood
building
ground such as a
connection
from a
cold
water
pipe
terminated
under
speaker
terminal II Gil on
the
amplifi
er.
Do not
connect
such a ground
wire
to
other
components In the system.
Excessive hum on
other
inputs may be
checked
in a
similar
manner.
Disconnect
the
Input
cable
In question and short
the
particular
input
jack
to
the
chassis. If
the
hum
dis-
appears,
the
trouble is
extemal
to
the
amplifier.
Note
that
on all inputs,
the
braid
of
the
Input
cable
should
con-
nect
to
the
amplifier
only
through
the
skirt of
the
Input
connector.
The
cause
and
remedies for
the
following symp-
toms
are
then based on
the
assumption
that
checks
made in
the manner
described
above
have
eliminated
the possibllity
of
the
trouble
being
external
to
the
amplifier.
If the
trouble
is no
output
or low
output,
checkAC
signal
voltages
and
DC
operating
voltages
starting
at
the
input
and working
step-by-step
toward
the
output.
Set
the
VOLUME control to maximum (10),
and
the
BASS
and
TREBLE
controls to
their
mid-points
(0). Use a 1000
eye
Ie
sinewave
signal,
such as supplied by the EICO
377
Sine &
Square
Wave
Audio
Generator.
In
addition,
use a
pre-
cision
100:
I
attenuator
to permit
obtaining
alevel of
0.01
volt
fedintoMAG.
PHONOfrom
an
audio
generator
output
of 1
.0
vol
t,
which
can
easily
be measured on
the
lowest
ACvolts
range
of yourVTYM(also improves signal
to humfrom
generator).
Use a high
input
Impedance
VTYM
for
allAC
signal
voltage
measurements (such as the EICO
232,249,221,
or
214)
and aVTYM
or20,000n/voltVOM
for DC
voltage
measurements.
If the troubl e is an
excessively
distorted
output,
try tube
replacement,
signal
tracing,
or
procede
directly
to vol
tage
and
resistance
measurements.
When the
defective
stage
is
localized,
precede
to a
resist-
ance
and
vol
tage
check
of the
stage,
using the
data
In the
VOLTAGEand RESISTANCE
chart.
Disconnect
the
ampll-
-fler
from
the
power
line
and
discharge
capacitors
prior to
making
any
resistance
check
and prior to removing
either
or both of the
EL84
output
tubes V4
and
V5.
Do not turn
the
amplifier
on with
either
of the
output
tubes
removed.
6
TROUBLE-SHOOTING A TYPICAL
TUBE
STAGE
1.
Check
tube.
2.
Check
plate
and
cathode
resistors.
3.
Check
coupling
capacitors
for
leakage
or short.
4.
For
output
stage,
check
de
resistance
of transformer
windings.
5.
Check
grid
leak
resistor for
open.
6.
Check
cathode
by-pass
capacitors
for short.
7.
If no or low
B+
voltage
on
tube,
check
decoupling
path for
open
or
defective
R18, R31, R32, R33 and
filter
capacitor
C17
or
C18.
8.
If wiring and
circuit
components
including
the
tube
check
O . K. and
B+
voltage
is
excessive,
check
the
de-
coupling
path
for short or
defective
R18, R31, R32, R33.
Suspected
trouble
in
the
equalization,
tone,
and
volume
controls
and
networks should
lead
to
specific
resistance
and
capacitance
checks
to
localize
the
trouble.
In
gen-
eral,
if
the
user suspects poor
frequency
response,
defec-
tive
equal
ization,
or
defective
operation
of the tone
con-
trols,
the
amplifier
should be
tested
thoroughly with
audio
generator,
vtvm,
and
scope.
SERVICE
If trouble
develops
in your instrument
which
you ccn
not
remedy yourself,
write
to our
service
department
listing
all possible
indications
that
might be
helpful.
Note
num-
ber
appeari
ng in red under
the
word"
ManuaP'
on
the
front
cover. If
there
is no number,
state
this. If desired, you
may return
the
instrument to our
factory
where
it wi II be
placed
in
operating
condition
for
$7.50
plus
the
cost of
parts
replaced
due
to
their
being
damaged
in the
course
of
construction.
NOTE: Before returning this
unit,
be
sure all parts
are
securely
mounted.
Attach
a
tag
to
the
instrument,
giving
your home address and
the
trouble
with
theunit
. Pack
very
carefully
in a rugged
container,
using
sufficient
packing
material
(cotton,
shredded newspaper,
or
excelsior),
to make
the
lonitcompletely
immovable
within
the
container.
The
original
shipping carton is
sat-
isfactory, providing
the
original
inserts
are
usedor
suffi-
cient
packing
material
is
inserted
to
keep
the instrument
immovable.
Shipby
prepaid
Railway Express, if possible,
to
Electronic
Instrument
Co.,
Inc.,
33-00
Northern Blvd. ,
Long Island
City
1,
N.
Y. Return shipment will be
made
by express
collect.
Note
that
a
carrier
cannot
be
held
liable
for damages in transit if
packing
IN HIS OPIN
ION,
is
insufficient.
SYMPTOM
Amplifier causes power
line
fuse
to blow. Power Iine fuse blows
a-
gain with V6
out
of
socket.
Amplifier causes power line fuse
to blow. Power line fuse does not
blow again with V6
out
of
socket.
Any or all tube filaments not
lit.
DC
voltage
at
V6
cathode
(pin 9)
is incorrect as specified below.
a) No
voltage
b) High
voltage.
c)
Low
voltage.
Excessive hum on mag. phono
or tope
head.
Excessive noise on mag.phono
and
tape
head
Sustained
oscillations.
Sustained microphonics on mag.
phono 'and
tape
head.
Hum on all inputs
TROUBLE-SHOOTING CHART
CAUS
E
Line
cord,
J6,
primary or high
voltage
secondary windings of T2 shorted
internally
or
externally
(wiring).
V6,
C17,
V4, V5,
or
T1
primary shorted
internally
or
externally.
Open
lead from
6.3V
winding of T2.
6.3V
winding of T2
open.
Defective
V6
C17 shorted
internally
or
externally.
Connection from C17 to pin 9 of V6 broken.
Connection to
center
tap of h. v , secondary
winding of
T2
open.
Output
tubes V4 &V5
over-biased
or not
drawing
current.
Excessive
current
drain in
amplifier.
Defective
V6
Vl
defective
Fil.
leads dressed too close to grid
lead.
Tube shield not making
electrical
contact
to base or base not making
electrical
con-
tact
to chassis.
Shielding and grounding of wiring to input
jacks not
exoctly
as instructed and shown
in drawings.
V1 socket and
contacts
dirty.
poor dress of output transformer
T1
leads
Vl
defective.
V2
defective,
not properly
shielded,
or
dirty sockets and
contacts.
Dress of power transformer 12
leads.
7
REM ED Y
Replace or repair.
Replace or repair.
Repair
Replace
Replace
Replace or
repair.
Repair
Repair
See trouble-shooting typical tube
stage.
See trouble-shooting typical tube
stage.
Replace
Replace
Dress fiI. leads awayfrom grid lead.
Check and
correct
Correct
Clean
throughly with carbon
tetrachloride.
Dress
all
input leads and
T1
leads
away. from
each
other.
Keep
T1
leads away from input lacks.
Replace
Replace,
correct,
or
clean.
Correct
VOLTAGE
AND RUtSTANCE
CHART
DC VOLTS DC VOLTS AC VOLTS (1kc)
RESISTANCE
TUBE
PIN'
NO
SIGNAL 12W OUT 12W OUT
UNIT
OFF
ECC83/12AX7 1108 108 0.52 300KO
VI
2 0 00.028
lMO
3
1.2 1.2
0
4.7KO
4&5
filament
(12 - 14DC;
6.3VAC
to pin 9)
165-1900
668 68 0.028 300KO
7 0 00.005 480KO
8 0.6
0.6
0.009
2.2KO
9
filament
165-1900
ECC83/12AX7 1 185 185 2 75KQ
V2
2000.5 500KO
3 1.4 1.4 0.265 1.2KO
4,5
filament
(12-14VDC;
6.3VAC to pin 9)
165-1900
6 180 180 1.38 130KO
7 0 0 0.26 400KO
81.6 1.6 0.135 3.3KO
9
filament
165 -
1900
ECC83/12AX7 1 190 190
7.7
120KO
V3 291 90 8 480Kn
393 92
7.7
IOCKO
4&5
filament
(12 - 14VDC;
6.3VAC
to pin 9)
165-1900
691 90 8480KQ
7001.37 210KO
80.85
0.8
1.25 1.8KO
9
filament
165-1900
ELM 1
V4 20 0
7.7
340KO
312 14.2 0.05
165-1900
4&5
filament
(12 - 14VDC;
6.3VAC
between)
165-1900
6
7 330 324 176
1600
8
9336 330
3.9
0
ELM 1
V5 2 0 0
7.7
340KO
312 14.2 .05
165-1900
4&5
filament
(12 - 14VDC;
6.3VAC
between)
165-1900
6
7 330 324 176
2000
8
9 336 330
3.9
0
EZ81 1- 280
950
V6 2
3336 330 160KO
4& 5
filament
(12 - 14VDC;
6.3VAC
between)
165-1900
6
7280
950
8
9 336 330 160KO
8
Section
AUX
TUNER
PHONO
TAPE
HEAD
1 - 11, 2 - 11,
3-10-11,
3-4-11,
Selector
A3 - 4
4-5
5-6
6-7
Switch
11 -
12,
1-11-12,
1 - 2 - 11 -
12,
1 - 2 -
12,
B2 - 3 - 5 3 -
5,
8-9
5 - 8,
8-9
9 - 11
Entries
are
numbers of those switch
contacts
which
are
connected
together
by the rotors
at
the
particular
position.
11
7VAC
~[]
M
OO
"
".,.
I I
I"!IGH F 'OE:.LlTV
1'2 W A
TT
AMF'
LI f-l i:.R 2
50
W
HUM
ADJUST
oI
'mm°(i)"Ci)
'I
OUTPUT
16 S 4 G
TOP
vlrw
AUX
TUNER
00
MAG.
TAPE
00
PHON
O
HEAD
V
-3
V - 2 0
o
ECCS3!12A
X7
ECCB3
!12AX7
M O Oi:. L
"''''2
"' .GH FIDE L" "
V-1
o
ECC
S3!12AX7
V
-4
o
EL S.4
V - 5
o
ELS4
V
-6
o
EZS1
POW
ER
CO
NS.UMP
TIO
N
l!Ll!CTRON
IC ',," S T co "', C
TRANSFORMER
TEMPERATURE
nONT
The temperature of the transformers used in
the
HF-12 run at less than
1950
despite
the
fact
that
the
safety
limitis
at a much
higher 221oF. Although
19SOF
is cool for a transformer, it is very hot to
the
touch.
Transformers
which
seem too hot when
touched
with
the
hand,
are
usually
good and
are
actually
not
overheating.
Output transformers usual!y run
cooler
than
powertransformers. Some
output
transformers may
appear
hotter
than others due
to being
located
near
hot components such as
output
and power tubes and power transformers.
OUTPUT TRANSFORMER LOAD
The output transformer and
the
output
tubes of any amplifier
are
subjected
to
severe
stress when
the
amplifier
is
operated
at
a high signal level without aload. To
protect
these components against possible damage, always
have
either
a
speaker
or
resistive load
connected
to
the
output
terminals of the amplifier
while
it is
being
operated.
9
REPLACEMENT PARTS LIST
Stock'
Sym. Description Arn't.
Stock'
Sym. Description Am't.
20050
Cl
cap.,
paper, .25 mfd - 200
V"
1 54003 TB8,3 terminal strip, 2 post 2
22517 C2,12,13 cap., dlsc.; .025mfd (25K or 25,0(0) 354013 TB10 terminal strip, 1 post
leftw/gnd
1
22549 C3
cap.,
dlsc., .003mfd (3K or
30(0)
1 90034
Vl,2,3
tube, 12AX7 3
22514
C4,6
cop., disc., 850mmf, 10% 2 90039
V4,5
tube, EL84 2
23020 C5 ccp.,
elec.,
25 mfd - 6 V
••
1 90038 V6 tube, EZ81 1
20044 C7 cap., molded, .25 mfd - 400 V co 1 97712 XII pilot assembly 1
20039 C8 cop., molded, .1 mfd - 400 V
."
1 97027 XVI socket, 9 pin min. top mount 1
22529 C9
cap.,
disc., 150mmf, 10% 1 97025 XV2-6 socket, 9 pin min. bottom mount 5
22539
Cl0,11
cop., dlsc., 200mmf, 10% 2 40000 nut, hex,
'6-32
25
22533 C14 ccp., disc., 47mmf, 10% 140001 nut, hex,
'3/8
5
23007 C15
cap.,
elec.,
50mfd -
25V
' • 140007 nut, hex,
'4-40
16
20043 C16 cap., molded, .03 mfd - 600 V • 1140008 nut, hex,
'8-32
12
23016 C17 cap., elec., 30mfd -
400V
•140026 nut, tin.
'8-32
6
24005 C18 ccp,;
elec
.,
20-40-4Omfd-400-350-350V
140027 nut,
an~le
tin
dual'8
2
22507 C19 cop., disc., .0022mfd, 10% (2.2K or 22(0) 141000 screw,
6-32
x
1/4
25
22523 C20 cop.; disc., .0068mfd, 10% (6.8K or 6800) 1 41003 screw,
'8-32
x
3/8
6
23014 C21 cap ., elec ., 10mfd - 6 V • , 1 41016 screw,
*4-40
x
1/4
12
92000
11
pilot light 1 41026 screw,
'4
-40 x
1/4
brass 2
50011
JI-2,3-4
jack, dual phono 2 41027 screw,
'4
wood 2
50014
J5
lack,
single phono 1 41028 screw,
*8-32
x 1 2
50016
J6
outlet, convenience 141045 screw,
116
P. K. brown finish 4
29751 PCl printed
circuit
141046 screw,
118-32
x3/8 brownfinish 4
10410
Rl,15
res., 100Ko, I/,ZW, *10% 241047 screw,
'8
P. K. 4
10431
R2,19,36 res.,
470m,I/XH,
*10% 342000 washer, lock,
'3/8
5
11526 R3,4 res., 200KO,1/2W, * 5% 242001 washer, flat,
'3/8
1
10423 R5 res., 2.2KO, 1/XH, *10% 142002 washer, lock,
116
22
10430 R6 res" 4.7KO, 1/XH, *10% 142007 washer, lock,
114
14
10407 R7,8 res., lMQ, 1/XH, *10% 242008 washer, lock,
'8
12
11504 R9 res., 9OKo, 1/2W, * 5% 142032 washer, flat,
'8
2
10400 Rl0,21,26,27res.,10KQ, 1/2W, *10% 443000 lug,
'6
2
18038
Rll
pot.,
300m,
audio taper (volume) 143004 lug,
'8
1
18033 R12 pot.; lMQ, linear taper (bass) 146000 grommet, 3/8 1
18034 R13, S2
pot.,
500m,
linear taper, CT (treble) 146006
feet,
rubber 4
10426 R14,32 res.,
33m,
1/XH, :tJO% 250012 insulator for 50011 2
10427 R16 res., 1.2KO,1/XH, *10% 1 51006 plug, phono 5
10420 R17 res., 3.3KO, 1/2W, %10% 1 53007 knobs 4
10853 R18 res., 10Ko, iw, %10% 157000 Iine cord 1
11543 R20 res.,
1.8m,
1/XH, % 5% 1 58004 wire, hook-up length
11527 R22,23 res., 100KO,1/XH, % 5% 2 58300 spoghetti length
10412 R24,25 res.,
330m,1/XH,
%10%
258408 coble, single conductor length
14600 R28 res.,
1650,
5W,* 5% 1 58410 cable, 4conductor length
11538 R29 res" 22KO, 1/2W, * 5% 1 58501 wire, bare
1122
length
19009 R30 por.,
1000,
(hum adjust) 180049 control plate 1
10422
R31
res., 68Ko, 1/2W, *10% 1 81084 chassis 1
10520 R33 res., 68Ko, 1/XH, * 5% 181091 bezel 1
10425 R34 res., 56Ko, 1/XH, *10% 181092 bottom pIate 1
10419
R35 res., 270Ko, 1/2W,
*10"~
1 81103 bracket, left 1
60049 SI switch, selector 181104 bracket, right 1
32005
T1
transformer, output 181105 perforated screen 1
30019 T2 transformer, power 189204 label, rear apron 1
54017 TBI terminal strip, 1 post upright 189205 label, tube layout 1
54500 TB2 terminal board, 4 post 1 97300 tube shield 1
54002 TB5 terminal strip, 1 post right
wlgnd
197710 jewel, red 1
54004
TB4,9 terminal strip, 2 post wlgnd 266052 manual of instruction (wired) 1
54015 TB6 terminal strip, 3 post, 2 left
w/gnd
166304 manual of instruction (kit) 1
54000 TB7,11,12 terminal strip, 1 post left 3
C20
AUX.
Jl
TUNER
J2
le
I I I
PHONOJ3
TAPE J4
--
-
__
M ,
cJ5
(;)TAPE
~29
(14
T1
T2
~
":"
8
~
Description
~
Description
~
Description
~
Descdption
~
Description
~
Description
CI
cop.,
•25mfd C13
cop.,
. 025 mfd
)4
Ieek, tope input R9 rel
.,90Kn.
v/z«.«
5'l(,
121 rei
.,
101CQ.
I/ZW,±IO% R33 re••,
681CQ.
1/ZW,'"
5'l(,
C2
cop.,
•025 mfd C14 cop
.,
47mmf,10%
)5
jock, tope output RIO rei
.,
IOICQ.
1/ZW,*IO%
R22
res.,
1001CQ.
I/ZW, * 5% R34
rei.,
561CQ.
I/ZW,±IO% •
C3
cop.,
3OOOmmf,
10% CIS
cop.,
50mfd - 25V
)6
convenience outlet Rll
pot.,
5OO1CQ.
oudio(volume) R23
res.,
l001CQ.
I/zw,
* 5% R35
res.,
2701CQ.
I/ZW, ",10%
C4
cop.,
85Ommf,lO% C16
cop.,
. 03 mfd - 600 V
11
b.Jlb, 147 R12
pet.,
lMn,.
linea'
(boss) 124
rei.,
3301CQ.
i
/r«;
±I0% R36
res.,
4701CQ.
!/2W,
",10%
C5
cap.,
25mfd-6V
C17
cop.,
30mfd
-400V
Rl res
.,
l001CQ.
I/ZW, ±10% R13
pot.,
5OO1CQ.
lineor(treble) R25
res.,
3301CQ.
1/ZW,
*10% 51 switch, seleetee
C6
cop.,
85Ommf,10%
CI8
cap.,
20-40-40
mfd- 400-350-350 R2
rei.,
470KQ, I/ZW,±IO% RI4 res
.,
331CQ.
I/ZW,±IO% R26 res
.,
IOKQ, I/ZW,*lO% 52 swlteh, on-off, port 01 R13
C7
cap.,
.25mfd-400V
C19
cop.,
2200mmf,10% R3 res
.,
2OO1CQ.
I/ZW, ± 5% RI5
rei.,
l00KQ, I/ZW, ±10'll. R27 rei
.,
10KQ,
1/ZW,±lO%
VI lube, 12AX7
C8
cop.,
.1 mfd
-400V
C20
cop.,
6800 mmf,10% R4
rei.,
2OO1CQ.
1/ZW,
± 5% R16
res.,1.21CQ.I/ZW,±10'll.
R28 rei
.,
165Cl,
SW,±
S'll. V2 lube, 12AX7
C9
cap.,
150mmf,10'll. C21
cop.,
10mfd·6V
R5 res
.,
2.21CQ.
1/ZW,
±10'll. RI7
res.,
3.31CQ. 1/2W,±10%
R29
res
.,
221<0,
1/2W,±
S'll. V3 lube, 12AX7
Cl0
cap.,
200mmf, 10% )1 [cek, aux, inp..It R6
rei.,
4.
71CQ.
I/ZW, ±1
O'll.
R18
res.,
IOICQ.
lW,±lO% R30 pot
.,
lOOCl,
(hum odJu.t) V4 tube, ELM
Cll
cop" 200 mmf, 10% J2 lock, luner Input R7
res.,
lMCl, 1/ZW,±IO'll. R19
res.,
470KCl, I/ZW, ±10% R31 res
.,
681CQ.
!/ZW,±IO'll. VS lube, ELM
C12
cap.,
.025mfd
J3 jock, phono input R8 res" lMQ, I/ZW,±IO% R20
res.,
1.8KCl, I/ZW, ± 5'l(, R32 re••,
331CQ.
1/ZW,±IO'lE. V6 lube, EZ81
it!;!&
12
WATT
INTEGRATED
HIGH
fIDELITY
AMPLIfIER
MODEL
HF
12
GENERAL
INSTRUCTIONS
The section of
the
manual beginning with this page is the CONSTRUCTION
section.
All pages in this section have page numbers followed by
"C"
(lC,
2C,
etc.).
The INSTRUCTION
section
resumes on the pages following the
CONSTRUCTION
section.
Note
thot
the CONSTRUCTION section is
located
centrally
in the book and may be removed without desrupting the INSTRUC-
TION section
that
both precedes it ond follows
it.
Care
taken in the construction of this instrument will reward the constructor
with many years of satisfactory
service
and
greater
confidence
in his instrument.
We urge you to
not
rush the
construction,
but to
take
all the time necessary
for proper assembly and wiring.
Furthermore, we urge strongly
that
you follow
the
wire and parts layout shown
in the pictorial diagrams as
closely
as possible. Very often wires
are
placed
as shown for a good reason, and
certainly
the
appearance
of the completed
Instrument will be improved and the
difficulty
of finding awiring error wiII be
reduced by the following the wire and ports layout shown.
UNPACKING
THE
KIT: Unpack the
kit
carefully
and
check
each
part
against
the parts Iist IncIuding those parts
that
are
mounted to the chassis. If you have
trouble identifying any parts refer to
the
pictorial diagrams or the
color
code
n
chart.
You will find
that
the
value
of a component will vary within the
allowable
circuit
tolerance.
For
example,
the
4.7KO,
±10%resistor
may measure
any-
where between
4.2KO
and
5.2KO.
Tolerances on paper
capacitors
are
sub-
stantially
greater,
and
the
tolerance
for
electrolytics
is usually +100% and
-50%.
CONSTRUCTION HINTS: USE
THE
BEST
GRADE OF ROSIN CORE
SOLDER
ONLY,
preferably one
containing
the new
activated
fluxes such as Kester
"Resin-Five",
Ersin
"Multicore"
or similartypes. UNDER
NO
CIRCUMSTAN-
CES USEACID CORE
SOLDER
OR ACID
FLUX
since
acid
flux
can
cause
se-
rious corrosion. Before soldering make a
certain
of a good mechanical
con-
nection.
Use a
clean,
freshly tinned soldering iron, no smaller than 100
watts,
and
place
the solder on the joint (not on the iron)so
that
the solder Is melted
by the
heat
from the joint
itself.
Do not remove the soldering Iron until the
solder flows and
check
to
see
that
the
resul ting joint is smooth and shiny when
the solder has
cooled.
There
are
two extremes to be avoided; too
little
heat
and too much
heat.
If too
little
heat
Is
supplied,
the joint will
appear
pitted
and
grey,
Indicating a rosin
joint
which is unsatisfactory. On the
other
hand,
If too much
heat
is appl ied to a
joint,
the parts
connected
to
It
may
either
change
value,
loose
their
protective
coating,
or break down . If you
are
sol-
dering close to a
part,
hold
the
lead between
the
part
and
the
joint being
sol-
dered with the tip of 0
pair
of longnose pliers. The pliers will
conduct
the
heot away and
prevent
the component from being unduly
overheated.
If for
any reason it Is necessary to resolder a
joint,
be sure to use new
solder.
It should also be noted
that
the leads on resistors,
capacitors,
and transformers
are
often longer than
required.
These leads should be trimmed to the proper
length when necessary. Do not
cut
any lead until you have
determined
the
required length when
the
lead is routed as shown in the diagrams.
BASIC
TOOLS
REQUIRED
: These basic tools
are
required for
the
construction
of the amplifier.
1. Screwdriver -
3/16"
to
1/4"
blade
2.
Screwdriver -
1/8"
blade
3.
Longnose piiers - 5 or 6"
4.
Diagonal cutters
5.
Soldering iron (100
watts),
or soldergun, or pencil iron (35 watts)
6.
Gas pliers
7. High
quality
rosin or
equivalent
synthetic
flux
core
solder.
Do..!!2! use
acid
or paste flux under any circumstances.
A set of spintites and a wire stripper
are
also very useful supplementary tools.
PARTS
IDENTIFICATION: Please
note
that
very many of the parts for which
color
coding is given
maynotbe
color
coded,
but
have
their values and ratings
printed.
The
letter
K is a multiplier(X1000) and on resistors or
capacitors
in-
dicates
that
the printed numerical
value
must be multiplied by
one
thousand
to
obtain
the
value
in ohms or micro-micro farads
respectively.
Note
also
that
one microfarad (mf) is
equal
to
one
million; micro-microfarads (mmf). To aid
in rapid
identificotion,
keep
in mind
that
5%,
10%,
and 20% resistors
are
color
coded whereas 1%resistor have
their
values printed; also
that
molded
tubular
capacitors
mayor
may not be
color
coded,
whereas disc
capacitors
and
electrolytics
will always
have
their
values
printed.
Please
note
the
following
relationships
between
the units used to express resistance or
capacity.
1,000,000
ohms
(0)
=1000 kilohms (KO) =I megohm (MO)
1,000,000
micro-micro farads (mmf)=1 micro farads (mf)
CONSTRUCTION
PROCEDURE:
The
complete
step-by-step
mounting and
wir-
ing procedure follows. To
keep
thedrawingsuncrowded
,unnecessary
repetition
of mounting or wiring
details
may be omitted.
Note:
The
abbreviation
(!=)
means
connect
but do not solder (until
other
leads have
been
connected)
. The
abbreviation
(S) means
connect
and solder.
Bend the ground lug tabs on
the
sockets toward the chassis to
prevent
acciden-
tal shorting to
the
socket
pins.
Fig. 1
e17
__
___ r'Y
nAr
l
/'
I / III JI'\ I
---+-
_rJr."\. I _
_______
XV4
TB6
TB11~
---TB3
XV6/
TB9
TB5
TB2
Xl1
TB1
XV5 J5
~
nJ6
»>
ii
'
C::
~;
-
_
J3-4
, ...... J"
~
R30
~
~
r
=--..
~,-"
.
,
.
'J1-2
TB10
_
XV3~
-TB4
XV2
------
~
XV1
TB7
--------
If'J :
---------./
TB
8
~
n
MOUNTING
INSTRUCTIONS
NOTE; The chassis in Fig. 1 appears in expladed view. The angles on which
the tube sockets
are
mounted
are
actua
Ily part of the chassis, but has been
moved up,
out
of the chassis, to make component mountings more obvious.
Refer to Fig. 3 for proper orientation of all components.
1.
(J)
Fig. 1. Mount the 9 pin miniature tube socket with shield base XVI
as shown. Use two
#4-40
screws,
two'4
lockwashers and
two'4-40
hex nuts.
2.
('4 Fig. 1. Mount the 9 pin. miniature tube socket XV6 as shown. Use
two
'4-40
screws, two #4 lockwashers and two
'4-40
hex nuts.
3.
(~
Fig. 1. Similar to the
above,
mount the 9 pin miniature tube sockets
XV2,XV3,XV4 and XV5 as shown. Use two
'4-40screws,
two
'4
lockwashers
and two
'4-40
hex nuts for each
socket.
4.
("~
Fig. 1. Mount the 4 screw terminal board,
TB2
from the outside of the
chassis as shown. Use two
*6-32
screws and two
*6-32
hex nuts. Under one
'6-32
hex nut, mount a *6 ground lug. Under the other
#6-32
hex nut, add a
1 post upright terminal strip,
TB
I, and a *6 lockwasher. .
5.
(tYFig.
1. Mount a 2 post terminal strip, TB3, as shown. Use
one'6-32
screw, one
'6
lockwasher and one
'6-32
hex nut.
6.
(01g.
1. Using the same mounting
hole,
mount a two post with ground
terminal strip, TB9, from the bottom and a two post terminal strip, TB8,'from
the top. Use one #6-32 screw, one
'6-32
lockwasher and one
'6-36
hex
nut.
7.
(...("Fig.
1.
Mount a 2 post with ground terminal strip, T84, as shown.
Use one
'6-32
screw, one
'6-32
lockwasher and one
'6-32
hex nut.
8. (0 Fig. 1. Mount a 1 post right with ground terminal strip, TB5, as
shown. Use one
'6-32
screw, one
'6
lockwasher and one
'6-32
hex nut.
9. ( ) Fig. 1. Mount
Cl'3
post, 2left with ground terminal
strip,
T86, as
shown. Use one
'6-32
screw, one
'6
lockwasher and one
'6-32
hex nut.
10. ( ) Fig. 1. Using the same hole , mount a 1 post left.terminal
strip,
TB7,
from the top and 30mfd
electrolytic
capacitor'"ICl7,
as shown.
Observe
the
polarity on the
capacitor.
Use one
'6-32
screw,
one'6
lockwasher
and
one
'6-32
hex nut.
11. ( )
Fi~.
1. Mount the
pilot
light
socket,
XII,
as shown. Use
one'6-32
screw, one 6 lockwesher and one
'6-32
hex nut.
12. ( ) Fig. 1. Mount a 1 post left with a ground terminal strip, TB10, as
shown. Use one
'6-32
screw,
one'6
lockwasher and one
'6-32
hex nut.
13. ( ) Fig. 1. Mount input jack board,
JI-2
as shown. Use a
bakelite
insulator between the board and the chassis. Use four
'6-32
screws, four
'6-32
lockwashers and four
'6-32
hex nuts.
14. ( ) Fig. 1. Mount the input Jack
board,
J3-4
as
above.
Use
bakelite
Insulator as
above.
Use four
'6-32
screws, four'610ckwashers and
four'6-32
hex nuts.
15. ( ) Fig. 1. Mount
tape
output
Jack,
J5,
as shown. Use
two'6-32
screws,
two
'6
lockwashers and two
'6-32
hex nuts.
16. ( ) Fig. 1. Mount the hum adjustment
pot,
R30 as shown. Use
one)/8
flatwasher, one
3/8
Iqckwasher and one
3/8
hex nut. Bend upper and lower
lugs so that they
neither
protrude over bottom of chassis or touch the chassis
proper.
17. ( ) Fig. 1.
Mounttheconvenienceoutlet,
J6 asshown. Use two
'6-32
screws, two
'6
lockwashers and two
'6-32
hex nuts.
18. ( ) Fig. 1. Push the grommet through the remaining
3/8
hole in the rear
of the chassis.
19. ( ) Fig. 1.
Mount'6
ground lug
"I".
Use a
'6-32
screw and a
'6-32
hex
nut.
See Fig. 5.
20. ( ) Fig. 1. Mount a 1 post left terminal strip,
TB
11, as shown. Use one
#6-32 screw, one
'6-32
lockwasher and one
'6-32
hex nut.
N
I-
I-
4C
00
U
N.
.
~
...
MOUNTING
INSTRUCTIONS
CONT'D.
1. ( ) Fig. 2. Mount the switch, S1, as shown.
Note
that
the switch is In
the maximum
counter-clockwise
position. Use one
3/S"
lockwasher and one
3/8"
hex
nutas
shown.
Note
that
tab on switch slides Into small hole
adjacent
to mounting hole.
2. ( ) Fig. 2. Mount the pot,
R11
(18038) as shown. Use one
3/S"
lock-
~
washer and one 3
/S"
hex nut.
Note
that
the tab on pot slides into small hole
adjacent
to mounting hole.
3. ( ) Fig. 2. Similar to the above, mount the pat R12 (lS033) and the pot
with the switch, R13 and S2 as shown. Note
that
in each
case,
the tab on the
potslldes into small hole
adjacent
to mounting hole. Use one
3/S"
lockwasher
and one
3/8"
hex nut In mounting
each
pot.
4. ( ) Fig. 2. Mount the
output
transformer,
T1
(32005) as shown. Use four
'S-32
hex
nuh
and four IS lockwashers.
Note
that the yellow lead and the
brown lead
face
the rear of the chassis toward T82.
5.
()
Fig. 2. Mount the power transformer, T2 (30019) as shown. Use four
'S-32
hex nuts and
fourlSlockwashers.
Add a IS ground lug under
one
of the
lockwashers as shown.
Note
thot the green leads
face
the
center
of
the
chassis
and the tube sockets XV4 and XV5.
6: ( , Fig. 2. Mount the
electrolytic
can
capacitor,
C1S as shown.
Note
the mounting in Fig. 3 as to direction of
triangle
,
semi-circle
and square,
next to the prongs on the
capacitor.
Insert the mounting tabs into the slots In
the chassis and twist the tabs somewhat less than a quarter tum. DO NOT
twist the tabs excessively or they wiII shear off. Solder one tab to the chassis
at
Its slot.
7. ( ) Fig. 2. Mount a 1 post left terminal strip,
TB12,
as shown. Use one
'6-32
screw, one
*6-32
lockwasher and one
'6-32
hex nut .
-.a>
~
J3-J4
J1-
J2
TB2
Tl
TB3
~
~
~
=te
C18
~
~~
7~
XV1
-;;;;-
\
~
~TB4
~
~~
TB9
XV2
elf>
~
J6
R30
T2
J5
TBl
R28
XV5
XV4
TB6
XV6
C15
TB5
XV3
~
Fig.3
~
WIRING
INSTRUCTIONS
1. ( ) Fig.
3.
Cut
a 6" length of
black
wire and 6" length of brown wire.
Connect
one end of the brown wire to
XVl-9
(5) and one end of the black wire
to
XVl-4
(5) through
XVI-5
(5). Twist the two wires and run along
the
chassis
as shown.
Connect
the
other
end of the black wire
toXV4-4
(C)and the
other
end of the brown wire to XV4-5 (C).
2. ( ) Fig. 3. Following
the
above
pracedure,
cut
a 4" length of black wire
and a 4" length of brown
wire.
Connectane
end of the black wire to XV4-4 (5)
and
one
end of
the
brown wire to XV4-5 (5). Twist the two wires and run
a-
long the chossls as shown.
Connect
the
black
wire to XV5-4 (C) and the brawn
lead to XV5-S (C).
3. ( ) Fig. 3. Following the above procedure,
cut
a 4" length of black wire
and a 4" length of brown wire.
Connect
one end of the
black
wire to XV5-4(5)
and
one end of the brown wire
toXV5-5($).
Twist
the
two wires and run along
the chassis as shown.
Connect
the black wire to XV3-5 (C) through XV3-4 (C)
and
the
brown wire to XV3-9 (C).
4.
( ) Fig. 3. Following the above
pracedure,
cut
a 3" length of black wire
anda
3"'ength
af brawn
wire.
Cannect
ane
end
oftheblackwire
toXV3-5(5)
and
one
end of
the
brown wire
toXV3-9(C).
Twist the two wires and run along
the chassis as shawn.
Cannect
the
black
wire to XV2-4 ($) through XV2-S (5)
and the brown wire to XV2-9 (5).
S. ( ) Fig. 3. Following the above
procedure,
cut
a 4" length of black wire
anda
4" length of brown
wire.
Connect
one end of the black wire
toXV3-4
(5)
and one end of the brown wire
toXV3-9(5).
Twist the two wires and run along
the chassis as shown.
Connect
theblack
wire
toXV6-S(C)
and the brown wire
to XV6-4 (C).
6.
( ) Fig.
3.
Following
the
above
procedure,
cut
a 6" length of black wire
and a 6" length of brown
wire.
Connect
one
end
ofthe
black wire to XV6-5 (C)
and one end of the brown wire
toXV6-4
(C). Twist the two wires and run along
the chassis as shown.
Connect
the black wire to
XIl-1
(5) and the brown wire
to XI1-2 (5).
7. ( ) Fig. 3. Following the above
procedure,
cut
a 6" length of black wire
and a 6" length of brown
wire.
Connect
one
endof
theblack
wire
toXV6-5(5)
and one end of the brown wire to XV6-4 (5). Twist the two wires and run along
the chassis as shown.
Connect
the
black
wire to R30-1 (C) and the brown wire
to R30-3 (C).
8.
( ) Fig. 3. Twist
the
two green leads fromthe power transformer, T2, and
run along the chassis as shown.
Connect
one green lead to R30-3 (5) and the
other green lead to R30-1 (5). '
9. ( ) Fig. 3.
Connect
a 6"
piece
of yellow
wirefromXV4-3
(C)toR30-2
(5).
10. ( ) Fig.
3.
Connect
a 3"
pieceofyellow
wire fromXV4-3
(5)toXVS-3
(C).
11. ( ) Fig. 3.
Cut
both leads of the
16SQ,
5W resistor, R28, to 1" . Put
3
/4"
of spaghetti on one lead and
leave
the
other
lead
bare.
Connect
the
lead
with the spaghetti to XVS-3 (C) and the
other
lead to ground
lug"
A" (5) on XV4.
12. ( ) Fig.
3.
Cut
the lead on the positive end (+) of the SOmfd, 2S
volt
electrolytic
capacitor,
CIS,
to I
1/2"
and the lead on the
negative
(-)
to I
1/4".
Put I
1/
4" spaghetti on the lead of the positive end and
connect
toXVS-3
(5).
Connect
the
negative
lead to ground
lug"
B"
(5) on XV6.
13. ( ) Fig.
3.
Cut
the lead on the positive (+) end of the
30mfd
capacitor,
C17,
to 2
1/2"
and the tead on the
negative
(-)
end to 3
/4".
Put 2
1/4"
spa-
ghetti on the positive lead and
connect
to XV6-9 (C).
Connect
the
lead
on
the
negat
ive end to
TB
10-2
(C).
14. ( ) Fig.
3.
Connect
a 1"
piece
of
bare
wire
fromXV6-9(5)toXV6-3
(C).
15. ( ) Fig.
3.
Twist
the
red leads from the power transformer, T2. Run the
leads along the chassis as shown.
Connect
one
red leadXV6-1 (5)and
the
other
red lead to XV6-7 (5).
16. ( ) Fig.
3.
Twist the
red-yellow
and the
white
leads from the power
trans-
former
T2
.
Connect
ta ground lug
"0"
(5).
17. ( ) Fig.
3.
Connect
one
black lead from the power transformer, T2, to
J6-1
(C) and
the
other
black
lead to
J6-2
(C).
18. ( ) Fig.
3.
Connect
an 8
1/2"
black
wire from
TBI
(C) to
XV3-8
(C).
19. ( ) Fig.
3.
Connect
the
following leads from the output transformer TI,
to the output terminal board
TB2:
Green
lead to TB2-3(5)
Yellow lead to TB2-4(C)
Brown lead to TB2-2(5)
Black lead to TB2-I(C).
20.
( ) Fig. 3.
Connect
a 3
1/2"
red lead from XV6-3(5) to XVS-9(C).
21. ( ) Fig.
3.
Connect
a 3 1/2" red lead from XVS-9(S) to XV4-9(C).
22.
( ) Fig.
3.
Connect
a 1"
piece
of
bare
wire from TB2-1 (5) to ground
"E" (5).
23.
( ) Fig.
3.
Connect
a 4"
piece
of black wire fromTB3-1 (C)toTB9-2 (C).
~
lEi>
~
_
,
~.
"-"- Wi
t-
=-
10
~
m
~
b-
-
-
"
~
" 0 0
~=
-
=.~""
.:-
~
_
~
~
....,
~I
,
'-./
\
-r-\\4
TB3
R32
R3
C21
I---R6
R7
XV1
C1
~
---t
----r-
I
R
10
-=---
~;t:==tt
C5
R5
R31
C2
R4
TB9
C18
R18
~I\TB4
~
J6
R30
J5
XV4
T2
XV5
TB6
TB5
XV3
XV6
~
C8
R17
R20
R15
C20
R14
XV2
R16
TB10
C7
TB
11
Fig. 4
Other manuals for HF 12
1
Table of contents
Other Eico Amplifier manuals
